[Code Style] member names start with underscore.

[dawidpilarski]

It is the dangerous naming convention, since implementations reserve all names starting with a double underscore and with single underscores following capital letters.

Even though it is not the case here, member names are started with an underscore and capital letter, it might be easy to fall into a trap.

It would be good to change the naming convention for underscores to follow the member name rather than precede the member name.